1. Field of the Invention
This invention relates to railroad-highway grade crossings, separations, and protection devices, particularly a new and improved combination with barrier gates, and devices to assist in maintenance of railroad tracks.
2. Description of the Prior Art
Attempts to prevent the damaging and frequently fatal interaction of railroad and highway traffic at grade crossings have included simple warning signs, usually black and white "cross bucks" of various forms and inscriptions; flashing red lights in conjunction with these signs on busier roads; and vertically swinging arm gates which, in the lowered position, block at least part of the roadway on its side of the tracks upon approach of a train. Alternately, highway overpasses or underpasses are built, at great expense, to completely eliminate the intersection of railroad and highway traffic. Many patents have been issued on various types of and improvements to railroad crossings, including warning signals, retractible speed bumps, gates and barriers.
The other aspect of my invention lies in the field of maintainability of highway-railroad grade crossings. A vast number of patents have been issued in this area, spread out over time from before the advent of the automobile to the present. Almost all patents cited in this area relate to fixed crossings which were proposed to be more durable, or easier to install or repair, than previous types. All cited prior art in this category has in common the utilization of the railroad track rail head as a portion of the automobile's riding surface, in that the top of the rails and the automobile riding surface are essentially coplanar, with material specified in their patents forming the roadway surface between the rails of a track and in most cases also forming the roadway surface for a short distance to the outboard side of each track rail. All but a few of these prior inventions call for the crossing material to occupy a fixed position relative to the railroad tracks, so that the crossing planks or slabs remain in the same position when a train rolls along the track over them, and in the same position they carry an automobile as it crosses the tracks by riding upon the crossing in question. Some of the prior inventions call for sprung flangeways, to keep dirt out, or cushioning of the surface on which automobiles ride, or hinges at the sections between the track rails, so that sections be loosened and swung up and removed manually when necessary to perform limited maintenance work on the railroad tracks between the rails. The present invention separates the planes of automobile-roadway contact and railroad rolling stock wheel tread-rail head contact sufficiently to allow the two to be completely distinct; mechanically raising the road surface at the crossing to form a barrier to automobile traffic while allowing railroad traffic to proceed through the crossing, with the complete track structure exposed when the roadway is raised, allowing unimpeded maintenance work to be performed on the railroad tracks; and lowering the highway surface onto the railroad track to allow passage of highway vehicles over the crossing.